Total joint arthroplasty, particularly total hip and total knees are being performed at an increasing rate in United States and in other developed countries. The estimated numbers are between 250,000 and 350,000 per year for each of the hip and knee joints. It is also estimated that about 10% of these joints fail at the end of ten years, and the failure rates increase with longer years of use. Due to the rapid increase in geriatric population, the number of patients requiring revision of a failed knee or hip arthroplasty is increasing.
In most total knee replacements, the majority of total hip joint replacements, and most other joint replacements, the implant is fixed to the bone with the help of a self curing acrylic cement (polymethylmethacrylate) called bone cement. In the revision surgery, the removal of the existing implant, reconstruction of the bone-stock and achievement of a stable fixation with a new component is often a difficult procedure. This is because bone cement is sometimes firmly bonded to the implant and surrounding bone, making it a technically demanding process to remove the implant without damaging the surrounding bone. For un-cemented hip and other joints, the implant is again firmly fixed to the bone, often due to in growth of bony tissue into the porous surface of the metal implant. The goal of such revision surgery is to remove the implant with minimum damage to the bone tissue. This is because the new implant needs bony support to be successful. Sometimes the difficulty in removing an implant causes the bone to fracture, and occasionally implant removal requires the surgeon to cut the bone itself to remove the implant. Thus, there is a definite need for new instrumentation to facilitate the removal of a cemented or un-cemented implant that will cause minimal damage to the bone tissue.
Needs exist for improved methods and apparatus for removing and inserting bone implants and rods, screws, plates and tooth and soft tissue implants.